Because it is difficult to cause a non-polar polyolefin, a rubber component, and the like to become soluble with or to adhere to a polar polymer, an inorganic material, and the like, various compatibilizers and adhesives have been developed. In general, polyolefins and rubber components modified with a polar compound are used. Such modified products have a high industrial value.
Specifically, a number of polyethylenes and polypropylenes modified with maleic anhydride or chlorine are commercially available. These modified products are used for applications such as a compatibilizer, adhesive, agglutinant, primer, and the like. They are produced using a modifier compound and/or a polar compound capable of forming radicals. This method, however, cannot introduce thermally instable substituents such as a (meth)acryloyl group into molecules.
As the method for introducing a thermally instable substituent, a method of previously introducing a substituent having reactivity with such a thermally instable substituent into the molecular end and introducing the target group via this reactive group can be given, for example. However, since a special catalyst system and polymerization technique are required in order to efficiently introduce a reactive group into the molecular end, this method is difficult to apply to industrial scale production. In addition, because the rate of introduction is low if such groups are introduced only to the ends of polymers, the effect of introduction is insufficient in many cases.
On the other hand, it has been disclosed that in the case of diene monomers, reactive groups such as a hydroxyl group can be efficiently introduced to the end of the polymer by using a special catalyst system (Japanese Patent Application Laid-open No. 50-18582). The hydroxyl group at the end is used for introducing suitable functional groups (Japanese Patent Applications Laid-open No. 62-148346 and 2002-371101).
The effect of introducing functional groups into ends is increased particularly in the case of a lower polymer having reactive groups at the ends, since the proportion of the end groups inevitably increases in the case of such a lower polymer. In addition, the effect of compatibility and adhesiveness is thought to be effectively controlled in a wide range if a suitable olefin compound is copolymerized with the main chain structure of a polymer having a reactive end.
The invention has been achieved in view of the above-described problem. An object of the invention is to provide a modified diene-α-olefin copolymer with improved compatibility and adhesiveness and a method for producing the same.